Half shell joint structure, an exhaust manifold including same, and a method for joining half shells

ABSTRACT

A half shell joint structure includes a first joint portion formed at an edge of a first half shell and a second joint portion formed at an edge of a second half shell. One of the first joint portions and the second joint portion has a protruding portion protruding by a predetermined interval in an outer diameter direction. The protruding portion has a flat contact surface, and when the first joint portion and the second joint portion overlap with each other, the contact surface contacts an inner surface of the joint portion that the contact surface faces.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority to Korean Patent Application No. 10-2016-0153561, filed on Nov. 17, 2016, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

The present disclosure relates to a half shell joint structure, an exhaust manifold including such a joint structure, and a method for joining half shells to each other.

BACKGROUND

An exhaust system of a vehicle typically utilizes a catalytic converter. One more recent type of catalytic converter is a close-coupled catalyst (CCC) type in which a catalytic converter is closely coupled to each runner of the exhaust manifold. Another type of catalytic converter is an under-floor catalytic converter (UCC) type in which a catalytic converter is connected to an exhaust manifold at a position relatively far away from the exhaust manifold. Thus, demand for uniformity of exhaust flow is relatively small, depending on a position of the catalytic converter. Design considerations include a layout of an engine compartment of the vehicle and an exhaust decrease demand level.

Metal materials, such as stainless steel, or the like, have been mainly used as a material of the exhaust manifold to improve fuel efficiency of the vehicle.

The exhaust manifold may be constructed having two half shells. Edges of the respective half shells may be joined to each other through welding to prevent leakage of exhaust gas.

In such a manifold construction, the edges of the respective half shells may be disposed to overlap each other and then joined to each other through welding.

However, a predetermined gap may be formed between the edges of the half shells due to a press (stamping, drawing, or the like) tolerance, i.e., an assembly tolerance of the respective half shells. Spatter (scattered slag or metal grains) generated at the time of welding the edges of the half shells may be introduced through the gap into an internal space formed by the two half shells. The spatter is introduced into the internal space of the exhaust manifold, such that cleanliness of the internal space of the exhaust manifold may be compromised.

Particularly, in a structure in which the catalytic converter is disposed adjacent to the exhaust manifold, such as a close-coupled catalyst (CCC) structure, or the like, the spatter may be introduced into the catalytic converter. Therefore, a chipping phenomenon occurs on an upper surface of a catalyst, such that purification efficiency of the catalyst may be decreased.

SUMMARY

The present disclosure has been made to solve the above-mentioned problems in the prior art while advantages achieved by the prior art are maintained.

One aspect of the present disclosure provides a half shell joint structure capable of preventing a catalyst from being damaged and maintaining cleanliness of an inner portion of an exhaust manifold. The disclosed joint structure blocks spatter from being introduced into a catalytic converter when a first shell and a second shell of the exhaust manifold are welded to each other. Another aspect of the present disclosure provides an exhaust manifold including the disclosed joint structure. A further aspect of the present disclosure provides a method for joining half shells to each other.

According to an embodiment of the present disclosure, a half shell joint structure forjoining a first half shell and a second half shell to each other by welding includes a first joint portion formed at an edge of the first half shell and a second joint portion formed at an edge of the second half shell. The first joint portion has a protruding portion protruding by a predetermined interval in an outer diameter direction. The protruding portion has a flat contact surface. With the first joint portion and the second joint portion overlapping each other, the contact surface contacts an inner surface of the second joint portion that the contact surface faces.

According to another embodiment of the present disclosure, a method for joining a first half shell and a second half shell to each other by welding includes a first step of forming a flange at an edge of the first half shell, the flange having a protruding part protruding by a predetermined length and a first joint portion that is flat at a portion of the edge of the first half shell adjacent to the protruding portion. The method also includes a second step of forming a second joint portion that is flat at an edge of the second half shell. The method also includes an overlapping step of overlapping the first joint portion and the second joint portion with each other such that the protruding portion contacts an inner surface of the second joint portion. The method further includes a welding step of welding the first joint portion and the second joint portion to each other.

In the first step, the flange may be cut or otherwise formed so that a flat contact surface is disposed at an end portion of the protruding portion.

According to still another embodiment of the present disclosure, an exhaust manifold includes a manifold body having two half shells. and a half shell joint structure joining the two half shells to each other. The half shell joint structure has a first joint portion formed at an edge of the first half shell and a second joint portion formed at an edge of the second half shell. The first joint portion has a protruding portion protruding by a predetermined interval in an outer diameter direction. With the first joint portion and the second joint portion overlapping each other, the protruding portion contacts an inner surface of the second joint portion that the protruding portion faces.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings.

FIG. 1 is a perspective view of an exhaust manifold according to one embodiment of the present disclosure, the exhaust manifold joined to a catalytic converter.

FIG. 2 is an exploded perspective view of the exhaust manifold of FIG. 1.

FIG. 3 is a cross-sectional view taken along line A-A of the exhaust manifold of FIG. 1.

FIG. 4 is an enlarged view of part of the exhaust manifold taken from circle B of FIG. 3.

FIG. 5 is a view a flange formed at an edge of a first half shell according to one embodiment of the present disclosure.

FIG. 6 is a view illustrating a process of cutting the flange of the first half shell of FIG. 5 by a cutter.

FIG. 7 is a view of a protruding portion that is formed at the edge of the first half shell after the flange of FIG. 6 has been cut by the cutter.

FIG. 8 is a view of a portion of the edge of the first half shell of FIG. 6 after being processed to form a first joint portion.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described in detail herein with reference to the accompanying drawings. For reference, sizes of components, thicknesses of lines, and the like, illustrated in the accompanying drawings referred to in describing the present disclosure may be exaggerated for convenience and understanding. In addition, since terms used in describing the present disclosure are defined in consideration of functions of the present disclosure. Such terms may be changed depending on the intention of users or operators, customs, and the like. Therefore, these terms should be defined based on the entire content of the present disclosure.

Referring to FIGS. 1-4, an exhaust manifold 10 according to an embodiment of the present disclosure may include a manifold body 20 having a first half shell 21 and a second half shell 22.

The manifold body 20 may include the first half shell 21 and the second half shell 22 joined to each other by welding. An edge 23 of the first half shell 21 and an edge 24 of the second half shell 22 may be joined to each other by welding 50 (see FIGS. 3 and 4) to form a half shell join structure 40.

The first half shell 21 and the second half shell 22 are joined to each other, such that one or more runners may be formed in the manifold body 20. In one embodiment, the one or more runners may be defined in the manifold body by shapes of the first half shell 21 and the second half shell 22. For example, as illustrated in FIGS. 1 and 2, the first half shell 21 and the second half shell 22 are joined to each other, such that a plurality of runners may be partitioned and formed in an internal space of the manifold body 20. The plurality of runners may be in communication with the respective cylinders of an engine through an inlet flange 28.

The inlet flange 28, through which exhaust gas is introduced during use on a vehicle, may be joined to one end of the manifold body 20 through welding, or the like. The inlet flange 28 may be joined to the engine, and may have openings that are in communication with the respective cylinders of the engine. The respective openings of the inlet flange 28 may be in communication with the respective runners.

An outlet portion 29, through which exhaust gas is discharged during use on a vehicle, may be formed at the other end of the manifold body 20. An inlet cap 61 of a catalytic converter 60 may be connected via an airtight joint to the outlet portion 29 of the manifold body 20. Since the catalytic converter 60 is directly coupled to an end portion of the manifold body 20 as described above, the catalytic converter 60 may be a close-coupled catalyst (CCC) type catalytic converter that is closely coupled to the runners of the manifold body 20.

Also in this embodiment, inner runners 30 (see FIG. 3) may be installed in the manifold body 20, depending on the vehicle engine specification or requirements, or the like, to form a dual-wall exhaust manifold. The number of inner runners 30 may correspond to that of the runners of the manifold body 20. Outer surfaces of the respective inner runners 30 may be spaced apart from inner surfaces of the respective runners of the manifold body 20 by a predetermined spacing or gap.

Referring to FIGS. 3 and 4, the half shell joint structure 40 according to an embodiment of the present disclosure is depicted. The half shell joint structure 40 may include a first joint portion 41 formed at the edge 23 of the first half shell 21 and a second joint portion 42 formed at the edge 24 of the second half shell 22. The first joint portion 41 and the second joint portion 42 may be joined to each other by a weld joint, i.e., the welding 50 to implement the half shell joint structure 40.

The first joint portion 41 may be formed at the edge 23 of the first half shell 21 and have a flat or straight shape or contour. Therefore, an inner surface and an outer surface of the first joint portion 41 may be flat. For example, the flat or straight shape of the first joint portion 41 may be formed by bending a portion of the edge 23 of the first half shell 21 twice at a predetermined bending radius (R). In one embodiment, it may be that the bending radius (R) is the same as a thickness (t1) of the first half shell 21. In the case in which the bending radius (R) is larger than the thickness (t1) of the first half shell 21, a crack, or the like, may be generated, such that molding, stamping, or drawing quality of the half shell may be deceased. Therefore, in one embodiment, the bending radius (R) may be the same as the thickness (t1) of the first half shell 21.

The second joint portion 42 may also be formed at the edge 24 of the second half shell 22 and have a flat shape or contour. Therefore, an inner surface and an outer surface of the second joint portion 42 may be flat. For example, the flat or straight shape of the second joint portion 42 may be formed by bending a portion of the edge 24 of the second half shell 22 twice at a predetermined bending radius (R). In one embodiment, it may be that the bending radius (R) is the same as a thickness (t2) of the second half shell 22. In the case in which the bending radius (R) is larger than the thickness (t2) of the second half shell 22, a crack, or the like, may be generated, such that molding, stamping, or drawing quality of the half shell may be deceased. Therefore, in one embodiment the bending radius (R) may be the same as the thickness (t2) of the second half shell 22.

A protruding portion 46 having a contact surface 45 may be formed on either one of the first joint portion 41 and the second joint portion 42. In the disclosed embodiment, the protruding portion 46 is described as provided on the first joint portion 41. One should understand, however, that the protruding portion can instead be provided on the second joint portion 42, and thus can be provided on either one of the first half shell 21 or the second half shells 22. Use of the terms in the written description and the claims in this context is intended only for ease of description and not to limit the scope of the disclosure to the protruding portion 46 being on a specific one of the half shells 21, 22. The contact surface 45 of the protruding portion 46 may be flat, and the flat contact surface 45 may contact an inner surface of the joint portion that it faces and form an air-tight joint or connection therebetween.

In this embodiment, with the first joint portion 41 and the second joint portion 42 overlapping each other, the contact surface 45 of the protruding portion 46 may contact the inner surface of the second joint portion 42. The protruding portion 46 may thus block or close a gap between the first joint portion 41 and the second joint portion 42. In this state, the welding 50 may be performed, i.e., the overlap may be welded such that the first joint portion 41 and the second joint portion 42 may be firmly joined to each other. It is noted that cutting the flange to form a protruding part protruding by a predetermined length and forming a first joint portion that is flat at a portion of the edge of the first half shell adjacent to the protruding portion may be performed simultaneously.

According to an embodiment of FIGS. 3 and 4, the protruding portion 46 may be formed at an end portion of the first joint portion 41.

A process of forming the protruding portion 46 at the end portion of the first joint portion 41 and a method for joining the first joint portion 41 and the second joint portion 42 to each other are now described in detail with reference to FIGS. 5-8.

As illustrated in FIG. 5, a portion of the edge 23 of the first half shell 21 may be bent at a predetermined radius (R) through a primary press or metal forming process to form a flange 43 that, in this embodiment, protrudes in an outward diameter direction or radially outward. Here, the bending radius (R) may be the same as the thickness (t1) of the first half shell 21. In the case in which the bending radius (R) is larger than the thickness (t1) of the first half shell 21, a crack, or the like, may be generated, such that molding, stamping, drawing, or bending quality of the first half shell 21 may be deceased. Therefore, it may be preferable that the bending radius (R) is the same as the thickness (t1) of the first half shell 21.

As illustrated in FIG. 6, the flange 43 may be cut by a cutting blade or the like, i.e., a cutter 65 in a secondary press or metal forming process. More specifically, the cutter 65 cuts the flange 43 in a vertical direction in a state in which the cutter 65 approaches the edge 23 of the first half shell 21. The cutting process leaves behind the protruding portion 46 such that the protruding portion 46 may protrude from the edge 23 of the first half shell 21 by a predetermined length s as illustrated in FIG. 7. The flange 43 is cut in the vertical direction by the cutter 65, such that the contact surface 45 is flat and faces radially outward or in an outward diameter direction and may be formed in the protruding portion 46.

Meanwhile, the protruding length s of the protruding portion 46 may be determined by a draft angle of the cutter 65. The draft angle ‘a’ of the cutter 65 may be an angle between the cutter 65 and the edge 23 of the first half shell 21. For example, in the case in which the draft angle ‘a’ of the cutter 65 is 12°, since sin 12°≈0.2, the protruding length s of the protruding portion 46 may be 0.2 mm.

After the protruding portion 46 and the contact surface 45 are formed, the first joint portion 41 may be formed at the edge 23 of the first half shell 21. The first joint portion 41, as noted above, can be formed to have a flat or straight shape or contour through a further press or metal working process whereby a portion of the edge 23 of the first half shell 21 is bent twice at the predetermined bending radius (R). As a result, the protruding portion 46 and the contact surface 45 may be formed at the end portion of the first joint portion 41.

The first joint portion 41 and the second joint portion 42 are disposed to overlap with each other when the first half shell 21 and the second half shell 22 are assembled to form the manifold body. The contact surface 45 of the protruding portion 46 of the first joint portion 41 may contact the inner surface of the second joint portion 42 by the overlap between the first joint portion 41 and the second joint portion 42.

In this overlapping state, the first joint portion 41 and the second joint portion 42 are then welded to each other, such that the first joint portion 41 and the second joint portion 42 may be firmly joined to each other.

The first joint portion 41 of the first half shell 21 and the second joint portion 42 of the second half shell 22 are disposed to overlap with each other in order to form the manifold body 20. The contact surface 45 of the first joint portion 41 may thus closely contact the inner surface of the second joint portion 42 of the second half shell 22 with air-tight contact. In this arrangement, the gap between the overlapping first joint portion 41 and the second joint portion 42 may be a specific dimension or interval, which is determined by the protruding length s of the protruding portion 46. More specifically, the protruding portion 46 may block or close the gap between the first joint portion 41 and the second joint portion 42. The protruding portion 46 thus can prevent spatter, which is generated at the time of welding the first joint portion 41 and the second joint portion 42 to each other, from being introduced through the gap into the half shell jointing structure 40 and thus into the inner portion of the manifold 10.

In the present disclosure, the protruding length s of the protruding portion 46 may be minimized. This can make it possible to minimize the width or dimension of the gap between the first joint portion 41 and the second joint portion 42. A limited gap size may then minimize a deformation amount of the first joint portion 41 and the second joint portion 42 at the time of welding the first joint portion 41 and the second joint portion 42 to each other.

For example, according to the related art, with a gap between joint portions of 0.3 mm, a deformation amount of the joint portions at the time of welding the joint portions to each other may be approximately 0.6 mm, which is two times or twice the gap size of 0.3 mm. On the other hand, the protruding length s of the protruding portion 46 in the disclosed embodiment may be minimized up to 0.2 mm depending on the draft angle of the cutter 65. Thus, the deformation amount of the joint portions at the time of welding the joint portions to each other may be maintained at 0.4 mm, which is two times or twice the gap size of 0.2 mm. The protruding portion 46 thereby makes it possible to minimize the gap, the deformation amount, and the like.

A half shell joint structure 40 according to one embodiment of the present disclosure is applied to the manifold body 20 of the exhaust manifold 10 and has been described and illustrated by way of example in the above-mentioned description and drawings. However, the half shell joint structure 40 according to the present disclosure is not limited thereto. In another embodiment, the joint structure 40 but may be applied to various fields such as various pipes, cases, and the like. For example, those having ordinary skill in the art will come to understand, upon reading this disclosure, that if the inner runner 30 of the exhaust manifold 10 consists of a half shell system, the half shell joint structure 40 described above may be applied to the inner runner 30.

As described above, according to the embodiments of the present disclosure, it is possible to prevent damage to a catalyst and to maintain cleanliness of an inner portion of the exhaust manifold by blocking spatter from being introduced into the catalytic converter when the first shell and the second shell of the exhaust manifold are welded to each other.

As noted above, the protruding portion 46 may instead be provided and formed on the second joint portion 42 of the second half shell 22. However, for the protruding portion to prevent spatter from entering the inner portion of the manifold 10, the welding 50 should be done from the outside of the manifold and, thus, the protruding portion should be within the gap, provided on the inner joint portion, whether that be the first or the second joint portion, and protrude in a radial outward or outward diameter direction. Further, the various manufacturing or method steps of forming the flange, cutting the flange, forming the first joint portion, and forming the second joint portion can each be performed separately in independent metal forming or metal working process steps. Alternatively, any one or more of these steps can be combined and be performed simultaneously with any one or more of the other steps or during the same step while working or forming the first and second half shell parts.

Although the present disclosure has been described with reference to various embodiments and the accompanying drawings, the present disclosure is not limited thereto, but may be variously modified and altered by those skilled in the art to which the present disclosure pertains without departing from the spirit and scope of the present disclosure claimed in the following claims. 

What is claimed is:
 1. A joint structure for joining a first half shell and a second half shell to each other by welding, the joint structure comprising: a first joint portion formed at an edge of the first half shell; and a second joint portion formed at an edge of the second half shell, wherein the first joint portion has a protruding portion protruding by a predetermined interval in an outward diameter direction, and wherein, where the first joint portion and the second joint portion overlap with each other, the protruding portion contacts an inner surface of the second joint portion with which the protruding portion overlaps.
 2. The joint structure according to claim 1, wherein a flat contact surface is formed on an end surface of the protruding portion.
 3. The joint structure according to claim 1, wherein the first joint portion is formed at the edge of the first half shell and has a straight or flat shape.
 4. The joint structure according to claim 1, wherein the second joint portion is formed at the edge of the second half shell and has a straight or flat shape.
 5. A method for joining a first half shell and a second half shell to each other by welding, the method comprising: a first step of forming a flange at an edge of the first half shell; a second step of cutting the flange to form a protruding part protruding by a predetermined length; a third step of forming a first joint portion that is flat at a portion of the edge of the first half shell adjacent to the protruding portion; a fourth step of forming a second joint portion that is flat at an edge of the second half shell; an overlapping step whereby the first joint portion and the second joint portion are overlapped with each other to allow the protruding portion to contact an inner surface of the second joint portion; and a welding step of welding the first joint portion and the second joint portion to each other.
 6. The method according to claim 5, wherein the third step of forming the first joint portion and the second step of cutting the flange are performed simultaneously.
 7. The method according to claim 5, wherein in the second step of cutting the flange, the flange is cut in a vertical direction by a cutter so that a flat contact surface is formed at an end portion of the protruding portion.
 8. An exhaust manifold comprising: a manifold body having two half shells; and a half shell joint structure joining the two half shells to each other, wherein the half shell joint structure has a first joint portion formed at an edge of the first half shell and a second joint portion formed at an edge of the second half shell, wherein the first joint portion has a protruding portion protruding by a predetermined interval in an outward diameter direction, and wherein, where the first joint portion and the second joint portion overlap with each other, the protruding portion contacts an inner surface of the second joint portion that the protruding portion faces.
 9. The exhaust manifold according to claim 8, wherein a catalytic converter is directly coupled to an end portion of the manifold body. 